More than 400 animal-lovers peacefully marched more than a mile through Havana on Sunday, shouting slogans and waving signs calling for an end to animal cruelty in Cuba.

Short, seemingly simple, the march wrote a small but significant line in the history of modern Cuba. The socialist government had explicitly permitted a public march unassociated with any part of the all-encompassing Communist state, a move that participants and historians call highly unusual and perhaps unprecedented since the first years of the revolution.

"I think it's very intelligent that they approved the demonstration, or, rather, march," said singer Silvio Rodriguez, an establishment figure who has criticized official cultural rigidity and who participated in the event. "It makes us feel optimistic. Now we have to see if the same thing will happen with other causes."

There is no indication Cuba is moving toward unfettered freedom of assembly: The state still clamps down on unapproved political speech with swift and massive police mobilizations, waves of arrests and temporary detentions. So a march by independent civil society groups seeking government action was a remarkable sight in a country where, for nearly 60 years, virtually every aspect of life was part of a single chain of command ending in a supreme leader named Castro.

"It's unprecedented," said Alberto Gonzalez, an organizer of the march and publisher of The Ark, an online Cuban animal-lovers magazine. "This is going to mark a before and an after."

Since shortly after its foundation, the Cuban Communist government has only permitted the existence of what it calls "legitimate civil society" — groups overseen, sponsored and managed by the state and Communist Party. Those groups are fixtures in the mass marches and gatherings organized by the state on public holidays. On the other end of the spectrum are dissident groups, often with close ties to anti-Castro forces in Miami who want to overthrow the socialist government and reinstall a capitalist system with close ties to Washington. Their attempts at street protests and other forms of organizing are almost instantly quashed by state security.

The animal-rights march was monitored by what appeared to at least a couple of dozen plain-clothes state security agents, who watched participants closely but did not interfere. Gonzalez said security officials had asked him to steer the march from the main thoroughfare where it had been authorized to a smaller side street in order to avoid traffic.

It was covered by virtually all major international media based in Havana, but did not appear to be covered by most state-run media, a fact that Rodriguez, the legendary singer, called a lost opportunity.

"It's a shame that after the march was approved, the national press hasn't covered it," he said. "It's sad."

In the year since Raul Castro handed the presidency to longtime party technocrat Miguel Díaz-Canel in April 2018, churches, civil society groups and loose associations of like-minded acquaintances have been using the growing availability of internet in Cuba to organize for various causes, and the state has been ceding them a small degree of freedom to operate.

Artists pushed back successfully against a new law regulating artistic expression. Evangelical churches prodded the government to rescind a proposal to legalize gay marriage. Thousands organized online to get private aid to victims of a tornado in Havana in January. Biologist Ariel Ruiz Urquiola was freed from prison after an online campaign by a wide range of Cubans against his one-year sentence for "disrespecting a forest ranger" during a broader campaign against illegal logging and other environmental violations in western Cuba.

"It's part of a trend toward recognizing civil society, in a tacit manner, sometimes a timid one, but one that's growing, little by little," said Yassel Padron Kunakbaeva, a blogger and intellectual who describes him as a Marxist revolutionary.

A 10-year-old private group known as Forest Guardians regularly organizes tree plantings and cleanups of rivers that cross the city of Havana, said organizer Isbel Diaz, a biologist. Last year, the group used $11,000 in small donations to buy a headquarters where it holds workshops and study groups with what it calls a leftist, anti-capitalist orientation.

Diaz said that the group's first cleanup of the Malecon promenade in 2010 had 14 members picking up trash as several dozen state security agents filmed, took photos and called out threats and insults.

"Activism in Cuba has taken place despite the state," Diaz said. "In my opinion, it's not because the state has felt the need to open up, but because it's had no other option than to accept reality and people with a lot of courage have defied the limits and pushed the boundaries back a little."

In contrast, when self-employed taxi drivers went on an informal strike to protest new regulations, they were met with a flood of inspections that forced many to stop working.

Animal-rights activism has been a fertile field for organizing in Cuba, where these are no laws against animal abuse and virtually every neighborhood has a resident or two who dedicate hours to feeding, treating and sterilizing street dogs and cats, sometimes with the help of foreigners donating supplies and funds.

The country has one officially recognized animal-rescue group, Aniplant, and perhaps a dozen other small, non-state organizations in Havana and other major cities. In recent years the groups have collected thousands of signatures asking for an animal-protection law, with no success to date.

"What I believe is that, if I live in this country I should try to fight for what I want in this country, and what I want is to help Cuban animals," said Grettel Montes de Oca Valdes, a professional dancer and founder of the group Cubans in Defense of Animals, whose members marched on Sunday. "I don't think that we should stop speaking out because if we stop speaking out nothing happens. That method is useless."

With dozens of participants walking dogs on leashes and even in baby strollers, the march ended at the grave of Jeannette Ryder, an American who fought for animal rights in Cuba at the start of 20th century. Aniplant has typically organized what it calls pilgrimages to the grave every April.

In a sign of remaining tensions between the official and unofficial in Cuba, many volunteers from the government-backed animal group boycotted Sunday's march and holding their own event next week.